B-17 aircraft lost en route to the USA

[Larry]

Presumably the 8th Air Force B-17s that flew back across the Atlantic from the UK were only those with crews who had completed a tour and were allowed to fly home? I doubt that B-17 were ever used as transports.

The reason I ask is that in researching details of Pilot Officer Alfred John De Laune Ruttledge DFC RCAF (J/15160) of 138 Sqn, I discovered that he was lost without trace on 15th December 1944 between the Azores and the USA, while hitching a ride home in a B-17 - and yet the USAAF losses for 15th Dec 1944 do not show any likely matches.

I had thought it could have been an RCAF aircraft but none used the B-17 and I doubt that a returning RCAF crew would have been able take their plane home with them.

So can anyone confirm the B-17 aircraft's identity?